A high-frequency signal flowing through conductors arranged on a circuit board to be transmitted from the circuit board to the outside thereof or a high-frequency signal taken into the conductors on the circuit board from the outside thereof is mostly dealt with as a signal which requires being put in a condition of electro-magnetic shield so as to prevent noises from mixing thereinto from the outside or to be inactive to leak out from the conductors on the circuit board. For transmitting the high-frequency signal from the circuit board to the outside thereof or for taking the high-frequency signal into the circuit board from the outside thereof, for example, through a coaxial cable, under the condition of electro-magnetic shield, a coaxial connector device provided to be mounted on a circuit board is used. With the coaxial connector device thus mounted on the circuit board, for example, another coaxial connector device (a mating coaxial connector device) connected with a coaxial cable through which the high-frequency signal is transmitted is coupled.
Such a coaxial connector device provided to be mounted on the circuit board comprises usually an insulating base operative to face close the circuit board, a signal-joining contacting conductor fixed to the insulating base for transferring a signal and a grounding contacting conductor fixed also to the insulating base and having a cylindrical side wall portion which surrounds the signal-joining contacting conductor to be supplied with a grounding potential so as to put the signal supplied to the signal-joining contacting conductor in a condition of electro-magnetic shield. When the coaxial connector device is mounted on a circuit board to be used, a mating coaxial connector device, to which a coaxial cable is connected, for example, is coupled with the coaxial connector device, so that the signal-joining contacting conductor comes into contact with another signal-joining contacting conductor provided in the mating coaxial connector device and the grounding contacting conductor comes into contact with another grounding contacting conductor provided in the mating coaxial connector device. With the coaxial connector device and the mating coaxial connector device coupled with each other in such a manner, a signal which requires being put in a condition of electro-magnetic shield is transferred, for example, through the coaxial cable connected to the mating coaxial connector device, under the condition of electro-magnetic shield which is brought about by the grounding contacting conductor having the cylindrical side wall portion for surrounding the signal-joining contacting conductor in the coaxial connector device. (As disclosed in, for example, patent document 1.)
When the previously proposed coaxial connector device such as disclosed in patent document 1 is mounted on the circuit board, the insulating base to which the signal-joining contacting conductor (a central conductor) and the grounding contacting conductor (an outside conductor) are fixed is placed on the circuit board to face close the same, the signal-joining contacting conductor is connected to a signal terminal provided on the circuit board and the grounding contacting conductor is connected to a ground-potential terminal provided on the circuit board. It is usual that a signal-joining terminal portion (a connecting portion) of the signal-joining contacting conductor is soldered to the signal terminal provided on the circuit board so that the signal-joining contacting conductor is connected to the signal terminal and a grounding terminal portion (a leg portion) of the grounding contacting conductor is soldered to the ground-potential terminal provided on the circuit board so that the grounding contacting conductor is connected to the ground-potential terminal. Therewith, the coaxial connector device is put in a condition for engaging with or disengaging from the mating coaxial connector device.